A myriad of articles and studies suggest the beneficial effects of meditation on physical, emotional, and psychological health and well-being. These advantages are far-reaching, including improving depression symptoms, anxiety, stress, and mental health disorders. We may understand the general benefits of meditation, but what are the biological, neurological, and chemical processes behind these outcomes? In this article, we get to the heart of these questions and discuss the latest research on the science behind mediation and the benefits you should know about.
Recalibration of the Autonomic Nervous System
An article in the National Institutes of Health (NIH) suggests the peripheral nervous system (PNS) and its subdivision, the autonomic nervous system (ANS), are the central regions affected by anxiety, stress, and other mental health disorders. Stephen Porges, professor of psychiatry at the University of North Carolina, is best known for his work in these areas and for developing the polyvagal theory. This theory discusses the interplay between the sympathetic and parasympathetic branches of the autonomous nervous system when dealing with trauma, mental health issues, and pain. His view also includes the vagus nerve that exits the brainstem and travels through almost every body part. The polyvagal theory encompasses the branches of the autonomous nervous system and their responses, including:
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Parasympathetic system – immobilization
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Sympathetic system – the fight or flight response
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Ventral vagal – social engagement
From Porges’ work, we know that the ventral vagal functions as a kind of brake that slows down the heart and other organs, allowing the system to calm down. Several mental health disorders leave individuals in the “fight or flight” mode. This mode results in feelings of anxiety, panic, and other psychosocial responses. Studies find that meditation and yoga practices are capable of significantly increasing vagal tone. When this happens, this action targets and calms the amygdala – the brain’s area contributing to emotional processing and sending distress signals to the hypothalamus. MRI scans show that after an eight-week course of mindfulness practice, the amygdala appears to shrink. As this region shrinks, the pre-frontal cortex, associated with executive brain functions such as concentration and decision-making, becomes thicker. The connectivity between these regions also changes. The bond between the amygdala and the rest of the brain gets weaker, while the connections between areas associated with attention and concentration become more robust, according to Scientific American.
Calming the Hypothalamic-Pituitary-Adrenal Axis
Chronic stress can lead to a dangerous combination of neuroendocrine, metabolic, and neuropsychological changes. One area that is significantly altered by stress is a network of hormones known as the Hypothalamic-Pituitary-Adrenal (HPA) axis. The HPA axis is dysregulated in stress and psychiatric disorders. It is also responsible for the neuroendocrine part of the stress response. This response is created by the hypothalamic release of corticotropin-releasing factor (CRF), also known as the corticotropin-releasing hormone. When CRF binds to CRF receptors on the anterior pituitary gland, the adrenocorticotropic hormone is released. This hormone binds to receptors on the adrenal cortex and stimulates the release of cortisol.
Recent evidence suggests that regular practice of meditation appears to cause down-regulation of the HPA axis. One pilot study randomly assigned young adults to Transcendental meditation (TM) training, followed by eight meditation practice weeks. To assess HPA axis functioning, salivary samples to evaluate cortisol awakening response (CAR) were collected. The results indicate that participants randomly assigned to TM had lower awakening salivary cortisol levels and a more significant drop in CAR from baseline to week-4 than the control group. The results of this study provide evidence that TM may impact the biological effects of stress, including the HPA axis.
Game-changing Anti-inflammatory Properties
In the Journal of Alternative and Complementary Medicine, multiple research studies have led to the discovery that inflammation can be controlled by stimulating the vagal nerve complex. Meditation, as well as yoga practices, has been shown to increase vagal tone significantly and, therefore, is not only effective against psychological issues but inflammatory-based diseases as well, including COVID-19.
These studies document the effects of a diverse range of meditative and yoga practices that promote anti-inflammatory activity and reduce pro-inflammatory cytokine activity, including natural killer (NK) cell activity and NK and T cell cytokine production. One study showed that six weeks of daily 20-minute sessions of mindfulness meditation resulted in a significant downregulation of a composite of pro-inflammatory genes and a significant reduction of the pro-inflammatory transcription factor kappa B (NF-κB).
Researchers also observed an increase of anti-inflammatory glucocorticoid receptor activity and increased type I interferon signaling – a factor linked to SARS-CoV-2 treatment. Other studies show decreases in the circulating levels of the pro-inflammatory cytokine interleukin (IL)-12 and increases of anti-inflammatory cytokine IL-10.
Meditation is often seen as an “alternative” approach to health and wellness in healthcare circles. Research is helping overcome this perception, and ten minutes of mindfulness could soon become part of our daily health regimen – improving the mind-body connection. Hopefully, through more research, protocols in primary and preventative medicine, psychiatric treatment, and similar medical fields will include meditation as a clinical standard of integrative care.
